How are other qualities of the stimulus (e.g. position, wavelength, frequency,
etc.) encoded by sensory afferents? (p. 235-237)
1) changes in the temporal pattern of spike activity
on a single fiber
(Morse code example - transmitting a
sequence of letters on a single line)
2) labeled line coding - a dedicated line for each
quality (for example, 26 lines, each representing a single letter of
the alphabet)
3) across fiber coding - the quality is encoded as
a pattern across multiple lines
(ASCII code used by your computer;
7 lines: A = 1000001; B = 1000010; C = 1000011; D = 100100; etc.)

What are some neurobiological examples of a labeled line code? (p. 236-237) -chemoreceptors that
are highly specific to one particular chemical substance (e.g. insect pheromones)
-dedicated sensory receptors for different stimulus
modalities in the somatosensory system (touch, pain, cold, etc.)

What are some neurobiological examples of an across-fiber (population)
code? (p. 238-240)
- broadly tuned chemosensory receptors that respond
to many different odorants
(e.g., apple pie is represented as an
across-fiber code in the mammalian olfactory system)
- sense organs that use range fractionation with broad,
overlapping receptive fields
(e.g. statocyst organ coding of tilt angle
in crayfish; proprioceptor encoding of arm position)

What does it mean for a sense organ to be under efferent control? (p. 243) the sense organ receives
efferent synapses from the CNS that typically modulate the responsiveness
of the sense organ

What are extrafusal and intrafusal muscle fibers; which ones are muscle
spindle organs associated with? (p. 244-245) -extrafusal muscle fibers
make up the bulk of skeletal muscle and provide the contractile force
-intrafusal muscle fibers are thin, thread-like fibers
running in parallel with the extrafusal muscle
-muscle spindle organs are associated with the intrafusal
fibers

What is the functional role of muscle spindle organs? (p. 245-248) they play a key role in
reflex tuning by providing the CNS with information about
the length of a muscle compared to its "intended" length

What is sensory reafference? (p. 249-250) the sensory input
that an animal receives as a consequence of its own movements
for example, neuromast organs in the llateral line system
of fish are stimulated by the fish's own swimming movements or the visual stimulation that occurs
when an animal moves its eyes across a static visual scene

How does efferent control influence sensory reafference? (p. 249-250) by decreasing sense
organ sensitivity at the appropriate time, efferent control can reduce
sensory responses responses to reafferent signals

What is an example of efferent control in protecting a sense organ from physical
damage? (p. 250) efferent signals help
protect the ear from excessively loud noises (more details in Chapter 12)

What is an example of efferent control in selective suppression of sensory
input? (p. 250-251) when a cat attends
to a salient visual stimulus (like a mouse), responses to other stimulus
modalities can be suppressed